1. Field of the Invention
The present invention relates to an opto-electric device.
The present invention further relates to a method of manufacturing an opto-electric device.
2. Related Art
An opto-electric device is a device that provides for an optical effect in response to an electric signal, or that generates an electric signal in response to an optical stimulus. Examples of the first are light emitting diodes, such as organic light emitting diodes. Nowadays various photoactive materials are known that convert an electric current into photon radiation. Photoactive materials may typically be any organic electroluminescent (“EL”) material, including, but not limited to, small molecule organic fluorescent compounds, fluorescent and phosphorescent metal complexes, conjugated polymers, and combinations or mixtures thereof. Examples of fluorescent compounds include, but are not limited to, pyrene, perylene, rubrene, coumarin, derivatives thereof, and mixtures thereof. Examples of metal complexes include, but are not limited to, metal chelated oxinoid compounds, such as tris(8-hydroxyquinolato)aluminum (Alq3); cyclometalated iridium and platinum electroluminescent compounds, such as complexes of iridium with phenylpyridine, phenylquinoline, or phenylpyrimidine ligands as disclosed in Petrov et al., U.S. Pat. No. 6,670,645 and Published PCT Applications WO 03/063555 and WO 2004/016710, and organometallic complexes described in, for example, Published PCT Applications WO 03/008424, WO 03/091688, and WO 03/040257, and mixtures thereof. Electroluminescent emissive layers comprising a charge carrying host material and a metal complex have been described by Thompson et al., in U.S. Pat. No. 6,303,238, and by Burrows and Thompson in published PCT applications WO 00/70655 and WO 01/41512. Examples of conjugated polymers include, but are not limited to poly(phenylenevinylenes), polyfluorenes, poly(spirobifluorenes), polythiophenes, poly(p-phenylenes), copolymers thereof, and may further include combinations or mixtures thereof. The choice of a particular material may depend on the specific application, potentials used during operation, or other factors.
For large area OLED lighting on flexible plastic substrates, a large current is required to drive the system. The present thin film materials used for the semitransparent electrode (e.g. ITO) have a large resistivity and the large currents give rise to a substantial voltage drop, which results in inhomogeneous light emission. The conductivity of the electrode layers could be improved by increasing their thickness. However, the thickness of the transparent electrode layer cannot be increased too much in order to avoid an unacceptably low transparency. The transparent electrode should transmit a substantial amount, i.e. at least 50%, preferably at least 80% of photon radiation impingent thereon. This can be photon radiation rendered by the opto-electric layer for transmission to outside the device, or can be photon radiation from outside the device for transmission to the opto-electric layer.
Accordingly for producing large area flexible OLED devices on plastic substrates there is a need for an electrically conductive structure to support the transparent electrode. For reducing the manufacturing costs, such structured metallization coatings will preferably be applied on rolls of plastic foil using an inline roll-to-roll web coating process.
Accordingly, for opto-electric devices, such as light emitting devices and electro-chromic devices, but also for photo-voltaic products there is a need for a metallization structure that on the one hand has a good electrical conductivity, while on the other hand has a high transmission for radiation.
WO2007/036850 describes an organic diode device that comprises an organic diode structure having an anode layer, a cathode layer and an organic layer. At least one of the anode layer and the cathode layer has a set of contact areas that are distributed over a face of said structure. A barrier layer hermetically covers said structure and is provided with a set of openings aligned with said set of contact areas. A metal conductor has been electroplated on said barrier layer and contacts the set of contact areas via the set of openings.
The electroplated metal conductor shunts the anode and the cathode, and therewith provides for an even voltage distribution over the area of a large organic diode device and therewith an even luminance.